NeXTStation Video Problem

[codepoet]

Picked up a NeXTSTation with matching monitor, keyboard and mouse this weekend -- only $250 complete. Seller reported that it worked last time he used it but that it was showing "diagonal lines" when he tested before the sale. I got it home, checked the logic board and clock battery, then fired it up. This is what I got. Image is stationary and stable...just useless.

Someone in a FB group suggested RAM, so I cleaned it up with contact cleaner and re-seated half (a full set of 4), then tried the other half. I noticed some white gunk around the RAM slots, but no obvious cap leakage. I do plan to re-cap, but I thought I'd check for signs of life after a bath (a trick that works on Color Classic logic boards that leak.) After thoroughly drying I re-assembled and powered back up -- no change. Same image on the screen. Finally I tried booting without RAM...same thing.

It seems like all of that should at least have changed the symptoms if the problem was on the logic board. Now I'm starting to wonder if the issue is in the monitor. Anyone have any ideas?

 

[stepleton]

That looks like a good raster to me, so I doubt it's the monitor, especially if it's stable.

Consider asking at http://www.nextcomputers.org/forums/ ?

 

[codepoet]

Thanks, cross-posted there. There doesn't seem to be nearly as much experience/expertise on Steve Jobs' "other" computers, so I'm casting as wide a net as I can for help!

 

[Jinnai]

You'll probably be able to reach Rob Blessin at nextcomputers.org, but if not, I was able to get help from him three years ago at the email address on this site: https://www.blackholeinc.com/specials/contact.shtml and he was very knowledgeable.

 

[codepoet]

Was able to rule out the monitor using a very hacky hack to get some signal directly to a separate VGA. I didn't know how to deal with the grayscale, so I just sent it to green -- and you can see the same pattern shown. So its something on the logic board. I guess I'll proceed with ordering some caps, and see if that fixes anything (but I doubt it)

 

[olePigeon]

That's a cool hack.

Could also post at VCF.

 

[joshc]

It's been a long time since I had a NeXT, and luckily I never had to troubleshoot mine.

There is a good chance recapping the logic board may fix it.

I'm rooting for you, I wish I'd never sold my NeXT, good luck with yours!

 

[NJRoadfan]

For black and white monochrome on VGA, send the mono signal to R,G, and B signal pins for white.

 

[codepoet]

Just to close the loop, this was ultimately resolved with a New Old Stock logic board. Someday I'll completely re-cap the original board, just to see if that fixes the problem. NextStation now running great with an external SCSI CD-ROM and an internal SCSI2SD upgrade.

 

[Huxley]

Hooray, congrats on a fantastic ending to this story!

I've had zero hands-on experience with NeXT machines* but I did wonder: as a Unix(ish) machine, would it have been possible to connect to it via Serial and access it via a boot monitor or something like that? I did this for my SGI Indigo2 machine last summer when I wanted to see if it could boot but lacked a compatible sync-on-green monitor to connect it to. I used a Serial-to-USB adapter and was able to see it booting via a Terminal window on my MacBook Pro, which was super helpful. Would this trick work on a NeXT machine too, if you can't otherwise get a good image from it?

H.

*If all goes well, this will be changing in the immediate future...

 

[archer174]

You can access over serial but the problem on the NeXT is that this option is not configured by default. You need to be able to boot into the machine to enable it which limits the usefulness... 

 

[archer174]

Just to close the loop, this was ultimately resolved with a New Old Stock logic board. Someday I'll completely re-cap the original board, just to see if that fixes the problem. NextStation now running great with an external SCSI CD-ROM and an internal SCSI2SD upgrade.

You'll want to recap that "new" logic board as well...